A fuel cell has been proposed as a clean, efficient and environmentally responsible energy source for electric vehicles and various other applications. In particular, the fuel cell has been identified as a potential alternative for the traditional internal-combustion engine used in modern vehicles.
One type of fuel cell is known as a proton exchange membrane (PEM) fuel cell. The PEM fuel cell typically includes three basic components: a cathode, an anode, and an electrolyte membrane. The cathode and the anode typically include a finely divided catalyst, such as platinum, supported on carbon particles and mixed with an ionomer. The electrolyte membrane is sandwiched between the cathode and the anode to form a membrane-electrolyte-assembly (MEA). The MEA is often disposed between porous diffusion media (DM) which facilitate a delivery of gaseous reactants, typically hydrogen and oxygen, for an electrochemical fuel cell reaction. Individual fuel cells can be stacked together in series to form a fuel cell stack. The fuel cell stack is capable of supplying a quantity of electricity sufficient to provide power to a vehicle.
During operation of the fuel cell stack, the fuel cell stack temperature is generally maintained within a desired range for the electrochemical fuel cell reaction. A coolant system having a coolant tank and coolant lines in fluid communication with the fuel cell stack is typically employed for this purpose. Coolant, such as substantially pure water, from a coolant tank is supplied to the fuel cell stack for regulating the temperature thereof. The coolant supplied to the fuel cell stack is typically desired to have a minimal electrical conductivity. If ions are present in the coolant, an electrical conductivity of the coolant increases and a power generation efficiency of the fuel cell stack decreases. To militate against the decrease in the fuel cell stack efficiency, an ion-exchange cartridge for removing ions in the coolant is typically employed in the coolant system.
Known ion exchange cartridges are disposed in-line between the coolant tank and the fuel cell stack. After sufficient usage, the exhausted ion exchange cartridge including a housing, connectors, and resin, must be replaced and properly discarded. Such service on in-line ion exchange cartridges is generally difficult. For example, access to the part of the engine compartment where the ion-exchange cartridge is disposed may be limited. Additionally, the line is necessarily opened to replace the in-line ion exchange cartridge, resulting in a draining of at least some of the coolant. An entry of contaminants from the environment into the coolant system during such service is therefore likely. A subsequent and undesirable clean-up of the coolant system following service is generally also required.
There is a continuing need for an ion exchange cartridge and method for servicing a coolant system having the ion-exchange cartridge that employs reusable parts, minimizes waste, minimizes a loss of the coolant during the service, and minimizes the exposure of the coolant system to contamination from the environment. Desirably, the ion-exchange cartridge also has an integrated housing with closing and sealing functions that facilitates a reusing and a refilling of the ion-exchange cartridge with service.